I've never understood the idea that Link must never talk in a movie. It's been part of the conversation ever since the dawn of online Zelda communities. The only reasons I ever hear are "They screwed up CD-i and the cartoon", "Link is a mute" or essentially "that's how it's always been in the games".
Like do people not realize that Link has had several instances of visible dialogue in the series? Yeah sure they could screw it up but Link is also not just one person and, if a movie were to be made, then it's likely it would be set in its own universe just like the Mario movie. If it sucks it basically doesn't matter because it can be easily disregarded.
I'm not super hyped over the idea of Illumination being in charge of the film. I think they were a good match for Mario, and the Mario film turned out pretty well. Zelda though? It has a completely different vibe from anything Illumination normally does. That being said, I'd still be willing to see how it pans out. A lot of "bad ideas on paper" have ended up creating good things in the past so who knows. If we get a bad movie it still won't impact the games either way.